Aminoglycoside:

What is the MOA for amikacin and what are its key potential side effects?

Fines to bacterial 30 S ribosomal subunits and interferes with mRNA binding and tRNA acceptor sites… Interferes with bacterial growth; Concentration dependent

Kidney damage, ototoxicity

Anaerobic bacteria, gram negative (Pseudomonas) bacteria, some mycobacteria, some gram-positive (Staph) bacteria

Cidal

Amphenicol:

What is the MOA for chloramphenicol and what are its key potential side effects?

Lipid soluble, binds to the 50S unit of the bacterial ribosome, inhibits proteins synthesis

Hind leg weakness, aplastic anemia in humans

Broad spectrum, gram-positive and gram-negative bacteria

Usually static but can be cidal in high concentrations

1st gen Cephalosporin:

What is the MOA for cephalexin and what are its key potential side effects?

Binds to PBP, inhibits bacterial cell wall synthesis, leads to bacterial lysis

Time dependent

G.I. upset

Best activity against gram-positive cocci, some activity against Graham negative bacilli

Cidal

3rd gen cephalosporin:

What is the MOA for cefovecin and what are its key potential side effects?

Binds to PBP, inhibits bacterial cell wall synthesis, leads to bacterial lysis

Time dependent

Minimal side effects

Staphylococcus, Streptococcus, pasteurella

Cidal

3rd gen cephalosporin:

What is the MOA for cefpodoxime proxetil and what are its key potential side effects?

Binds to PBP, inhibits bacterial Wall synthesis, leads to bacterial lysis, inhibits production of peptidoglycan

Time dependent

G.I. associated symptoms

Most gram-positive bacteria and Graham negative bacteria

cidal

Lincosamide:

What is the MOA for clindamycin and what are its key potential side effects?

Inhibits protein synthesis through binding of the 50 S ribosome subunit

GI

Do not give to rodents, rabbits, horses or ruminants

Gram-positive cocci, anaerobic bacteria, gram negative rods

static

Lincosamide:

What is the MOA for lincomysin and what are its key potential side effects?

Inhibits proteins synthesis through binding of the 50 S ribosomal sub unit

GI

Gram-positive cocci, anaerobic bacteria, Gram negative rods

static

Penicillin/Clavulanate:

What is the MOA for amoxicillin clavulanate and what are its key potential side effects?

Binds to PBP and inhibits bacterial cell wall synthesis, prevents inactivation by some beta-lactamases

Time dependent

G.I., rare allergic reactions

Gram-positive cocci and bacilli, some gram-negative bacilli, beta lactamase producing staphylococci

cidal

2nd gen Fluroquinolone:

What is the MOA for ciprofloxacin and what are its key potential side effects?

Inhibits DNA gyrase and interferes with DNA/RNA synthesis

concentration dependent

G.I., cartilage injury in young puppies

Broad spectrum, Graham negative bacilli, some gram-positive cocci (staphylococcus)

cidal

2nd gen Fluroquinolone:

What is the MOA for enrofloxacin and what are its key potential side effects?

Inhibits DNA gyrase and interferes with DNA/RNA synthesis

concentration dependent

G.I., cartilage injury and young puppies, blindness in cats

Broad spectrum, gram-negative bacilli, some gram-positive cocci (staphylococcus)

cidal

3rd gen Fluroquinolone:

What is the MOA for marbofloxacin and what are its key potential side effects?

Inhibits DNA gyrase and interferes with DNA/RNA synthetase

concentration dependent

G.I.

Broad spectrum, gram-negative bacilli, some gram-positive cocci (staphylococcus)

cidal

Ryfamycin:

What is the MOA for rifampin and what are its key potential side effects?

Inhibits RNA synthesis

Liver toxicity, weekly chemistry is recommended

Potent P450 inducer

Tears, urine, saliva may be stained orange

Gram-positive bacteria, intracellular organisms

cidal

Sulfonamide:

What is the MOA for ormetoprim-sulfa/TMS and what are its key potential side effects?

Prevents folate synthesis and utilization

allergic reactions, liver damage, KCS, skin reactions, anemia, poly arthritis, associated with the EM, hypothyroidism (reversible substrate inhibitor of thyroid peroxidase, prevents iodination and coupling of tyrosine residues necessary for formation of thyroxine and thyronine, binds thyroglobulin and inhibits hormone function)

Monitor STT, avoid in Doberman pincher’s

Broad-spectrum, gram-positive and gram-negative bacteria

Static when used alone cidal in combo

Tetracycline:

What is the MOA for doxycycline/minocycline and what are its key potential side effects?

Binds to the 30 S ribosomal subunit and inhibits proteins synthesis

G.I., teeth/bone formation in young animals, esophageal stricture in cats

Doxycycline will kill horses if given IV

Broad-spectrum including some protozoa and most tickborne diseases

static

Beta lactam:

What is the MOA for amoxicillin and what are its key potential side effects?

Inhibits bacterial cell wall synthesis

Time dependent

G.I. upset

Do not use for skin

Nero spectrum, Streptococcus and non-beta-lactam producing staphylococcus, small number of Gram negative organisms

Cidal

Cloxicillin is Similar but more Resistant to be the lactamase and has better activity against gram-positive bacteria

Beta lactam:

What is the MOA for ampicillin and what are its key potential side effects?

Inhibits bacterial cell wall synthesis

Drug allergy

Nero spectrum, Streptococcus and non-beta-lactam producing staphylococcus, small number of gram negative organisms

cidal

1st and 2nd gen cephalosporins:

What is the MOA for cefaclor (2nd)/cefoxadril (1st)/cefazolin (1st) and what are its key potential side effects?

Inhibits bacterial cell wall synthesis

Time dependent

G.I., do not use if patient has allergy to beta lactams

Good activity against gram positive cocci, more broad spectrum to gram negative then first generation

cidal

• Best activity against gram-positive cocci, useful for Sone Gram negative bacilli

Cidal

Slightly more active against Gram negative enterobacteria

cidal

3rd gen cephalosporin:

What is the MOA for cefotaxime and what are its key potential side effects?

Inhibits bacterial cell wall synthesis

time dependent

do you not use in patients with allergies to Bader lactams

Injectable, expensive and needed frequently

More active against Graham negative bacilli not as active against staphylococcus

cidal

3rd gen Cephalosporin:

What is the MOA for ceftiofur and what are its key potential side effects?

Inhibits bacterial cell wall synthesis

Time dependent

Bone marrow suppression in dogs, CBC monitoring with long-term treatment

Good activity against Graham negative bacilli not as active against staphylococcus compared with other cephalosporins

cidal

3rd gen Cephalosporin:

What is the MOA for ceftazidime and what are its key potential side effects?

Inhibits bacterial cell wall synthesis

Time dependent

Do not use with beta-lactam allergy

Good activity against Pseudomonas

cidal

Beta lactam/carbapenem:

What is the MOA for imipenem and what are its key potential side effects?

Inhibits cell wall synthesis through binding to a specific PBP, causes rapid cell wall lysis

Neurotoxicity is possible

Expensive

Broad-spectrum including enterobacteria, Pseudomonas and can be active against gram-positive bacteria

cidal

Beta lactam/acyulreid openicillin:

What is the MOA for piperacillin/ticaricillin and what body system is it most appropriate for?

Good activity against Pseudomonas and used in EAR treatments (Very short half-life = limited systemic use)

cidal

Lincosamide:

What is the MOA for erythromycin and what are its key potential side effects?

Inhibits the 50 S ribosomal subunit

diarrhea, vomiting

Do not use in rodents = fatal

Effective at killing gram-positive bacteria, aerobic bacteria and mycoplasma

static

Macrolide:

What is the MOA for Tylosin and what are its key potential side effects?

Inhibits the 50 S ribosomal subunit

can cause but also treats diarrhea

Do not use in rodents horses or rabbits = fatal

Treats gram-positive bacteria, aerobic bacteria and clostridium/Campylobacter

Can be used to treat erysipelas in swine (penicillin would also be an appropriate treatment)

Nitrofuran antibiotic:

What is the mechanism of action for nitrofurantoin and what are its key potential side effects?

Inhibits ribosome function, impairing DNA/RNA synthesis

V/D

Nitrofuran antibiotic/Antiprotozoal:

What is the mechanism of action for furazolidone and what is it typically used to treat?

A monoamine oxidase inhibitor (these drugs are classically used as anti-depressants) With activity against protozoa, including Giardia

Local use in the G.I. only, not for systemic administration

Nitrofuran antibiotic/antiprotozoal:

What is the mechanism of action for pyrimethamind and what are its key potential side effects?

Inhibits folate synthesis

Folic acid anemia - monitor CBCs with use

Best for protozoa and neospora

Combine with sulfonamide for synergy

Aminoglycoside:

What is the mechanism of action for Gentamicin and Tobramycin? wWhat are key potential side effects?

Inhibits the 30 S ribosomal subunit

Concentration dependent

nephrotoxicity, ototoxicity - Monitor Reno values + urinanalysis

Broad spectrum, including staphylococcus and Enterobacter not as effective for Streptococcus and anaerobic bacteria

cidal

Gentamicin - Used topically in ears

tobramycin - Often in appointments, can be used in ophthalmic preparation’s

Sulfonamide plus salicylic acid:

What is sulfasalazine used to treat?

Idiopathic colitis

has similar side effects to sulfa drugs

increases metabolism of cyclosporine (all sulfonamides do!)

Nitroimidizole, antibiotics, antiprotozoal:

What is the mechanism of action for metronidazole and what is it used to treat? What side effect do we need to be aware of, especially in cats?

Generates nitrogen free radicals that damage DNA

affective against anaerobic bacteria and protozoa, generally used to treat diarrhea

can cause CNS toxicity especially in cats

static

Fluoroquinolone:

What is the mechanism of action for orbifloxacin and what are its key potential side effects?

Inhibits DNA gyrase

Concentration dependent

CNS toxicity, V/D, arthropathy in puppies possible blindness in cats

Giving with aluminum, iron or calcium containing medication will decrease absorption

Broad-spectrum including staphylococcus, Gram negative bacilli and some Pseudomonas

cidal

3rd gen Fluoroquinolone:

What is the mechanism of action for pradofloxacin and what are its key potential side effects?

Enhanced activity against DNA gyrase and topoisomerase

concentration dependent

bone marrow suppression

Even broader spectrum, effective against E. coli, staphylococcus, anaerobes and also mycobacteria

cidal

Reserved for use in people to treat MRSA

Novobiocin - binds DNA gyrase and ATPase

Vancomycin- binds cell wall precursors and inhibits so wall formation; can cause bone marrow suppression, neutropenia and kidney injury

Macrolide/azalide:

What is the mechanism of action for azithromycin and what are its key potential side effects?

Inhibits ribosome proteins synthesis

V/D possible

Has immune modulatory effects and has been suggested to be useful for treating viral papilloma

Macrolide:

What is the mechanism of action for clarithromycin and what are its key potential side effects?

Inhibits ribosome or proteins synthesis

time-dependent

V/D possible

Mycobacteria, gram-positive bacteria

static

May be more effective than erythromycin or azithromycin

Antiprotozoal an anti-malarial - effective against toxoplasma and Sarcocystis

Blocks folate/nucleic acid synthesis

May cause bone marrow suppression, folic acid anemia, diarrhea - Monitor CBC

Polypeptide antibiotic:

What is the mechanism of action for polymyxin B and what are its key potential side effects?

Cationic detergent, disrupts lipid cell wall

kidney injury

Reduced efficacy in the presence of pus

Generally used to topically

Pseudomonas! And other drug resistant bacteria

Cidal… Stabs holes in cell wall

A topical ointment that inhibits RNA and proteins synthesis

Cidal to staphylococcus and Streptococcus including MRS

May cause itching or burning in open lesions

Tetracycline:

What is the mechanism of action for tetracycline and what are its key potential side effects?

Inhibits the 30 S ribosomal subunit

Time dependent

Can cause orange teeth staining, abnormalities in bone formation and possible hepatotoxicity

Broad-spectrum including intracellular bacteria

static

Ocazolidinone:

What is the mechanism of action for linezolid and what are its key potential side effects?

Unique method of ribosome or inhibition where resistance is unlikely to occur

Gastric irritation, possible bone marrow toxicity with long-term treatment, monitor CBC if using long course

Generally reserved for human use

The 5 mechanisms of antimicrobial resistance are:

1) production of drug inactivating enzymes

2) modification of an existing target

3) acquisition of a target by-pass system

4) reduced cell permeability

5) drug removal from the cell.

-Inhibit iodine conversion to iodide, inhibit binding of iodide to thyroglobulin, interfere with the coupling of iodothyrosines

-Decreased TT4, fT4, TT3, fT3, and rT3 and increases in TSH may be seen within 2 weeks; may take >3 weeks to return to normal after the treatment is stopped

1) Limit drug uptake

2) modification of drug target

3) inactivation of a drug

4) active efflux of a drug

• Methicillin: acquisition of nonnative gene (mecA) encoding a penicillin-binding protein (PBP2A) 
• Rifampin: mutations lead to change in the structure of beta subunit of RNA polymerase
• Clindamycin: causes target site modification (ribosomal methylation or mutation and prevents binding of antibiotics to ribosomal target (erm genes)
• Aminoglycosides: reduced uptake, decreased cell permeability, or alteration of ribosomal binding sites
• Fluoroquinolones: alteration of target enzyme DNA gyrase and topoisomerase IV and changes in drug entry/efflux

• 1st choice is amoxicillin
• 2nd choices including erythromycin, clindamycin, doxycycline, chloramphenicol 
• 3rd generation cephalosporins

• 1st choice is TMS
• 2nd choice including minocycline, erythromycin and doxycycline

• Inhibit iodine conversion to iodide
• inhibit binding of iodide to thyroglobulin
• interfere with coupling of iodothyrosines
• Decreased TT4, fT4, TT3, fT3, rT3 and increases in TSH may be seen in 2 weeks
• may take >3 weeks to return to normal after treatment is stopped